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Scientists Map Out How to Nudge Small Asteroids into Earth’s Orbit
"The notion of an asteroid headed for Earth is typically seen as a bad omen.. On
the flip side, some scientists and entrepreneurs increasingly see this scenario as a potential opportunity. Deliberately redirecting asteroids to our planet’s vicinity could enable us to study them up close, or even mine them. Given that these objects are packed with valuable resources, building a collection of them nearby could spark major advances in spaceflight, to say nothing of the scientific research that might result from easy access to these extraterrestrial bodies. A recent paper published in Acta Astronautica suggests that asteroids could be captured in Earth’s orbit with aerobraking, a maneuver that uses atmospheric drag to decelerate and position objects in stable trajectories around a planet. Aerobraking has helped place interplanetary spacecraft in orbit around Mars and Venus, and to slow down spacecraft returning to Earth. Led by Minghu Tan, a PhD student at the University of Glasgow, the paper immediately addresses the most obvious concern with this scenario: What if there’s some mistake in the redirect process and an asteroid accidentally impacts Earth? It’s bad enough that the dinosaurs were oblivious to their doomsday space rock, but it would be especially embarrassing if we humans smack ourselves in the face with one." See: https://motherboard.vice.com/en_us/a...o-earths-orbit |
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Scientists Map Out How to Nudge Small Asteroids into Earth’s Orbit
On Monday, September 3, 2018 at 7:29:47 PM UTC-4, wrote:
"The notion of an asteroid headed for Earth is typically seen as a bad omen. On the flip side, some scientists and entrepreneurs increasingly see this scenario as a potential opportunity. Deliberately redirecting asteroids to our planet’s vicinity could enable us to study them up close, or even mine them. Given that these objects are packed with valuable resources, building a collection of them nearby could spark major advances in spaceflight, to say nothing of the scientific research that might result from easy access to these extraterrestrial bodies. A recent paper published in Acta Astronautica suggests that asteroids could be captured in Earth’s orbit with aerobraking, a maneuver that uses atmospheric drag to decelerate and position objects in stable trajectories around a planet. Aerobraking has helped place interplanetary spacecraft in orbit around Mars and Venus, and to slow down spacecraft returning to Earth. Led by Minghu Tan, a PhD student at the University of Glasgow, the paper immediately addresses the most obvious concern with this scenario: What if there’s some mistake in the redirect process and an asteroid accidentally impacts Earth? It’s bad enough that the dinosaurs were oblivious to their doomsday space rock, but it would be especially embarrassing if we humans smack ourselves in the face with one." See: https://motherboard.vice.com/en_us/a...o-earths-orbit Using aerobraking is a rather touchy affair. It implies a high thrust impulse on the asteroid to begin the transfer orbit. A small impulse to use gravitational capture allows the use of an emergency escape engine to eject a failed capture. Small vectoring to one of the L orbits and a mass limit rule would be an alternative. |
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Scientists Map Out How to Nudge Small Asteroids into Earth's Orbit
wrote on Mon, 3 Sep 2018 18:18:21 -0700
(PDT): On Monday, September 3, 2018 at 7:29:47 PM UTC-4, wrote: "The notion of an asteroid headed for Earth is typically seen as a bad omen. On the flip side, some scientists and entrepreneurs increasingly see this scenario as a potential opportunity. Deliberately redirecting asteroids to our planets vicinity could enable us to study them up close, or even mine them. Given that these objects are packed with valuable resources, building a collection of them nearby could spark major advances in spaceflight, to say nothing of the scientific research that might result from easy access to these extraterrestrial bodies. A recent paper published in Acta Astronautica suggests that asteroids could be captured in Earths orbit with aerobraking, a maneuver that uses atmospheric drag to decelerate and position objects in stable trajectories around a planet. Aerobraking has helped place interplanetary spacecraft in orbit around Mars and Venus, and to slow down spacecraft returning to Earth. Led by Minghu Tan, a PhD student at the University of Glasgow, the paper immediately addresses the most obvious concern with this scenario: What if theres some mistake in the redirect process and an asteroid accidentally impacts Earth? Its bad enough that the dinosaurs were oblivious to their doomsday space rock, but it would be especially embarrassing if we humans smack ourselves in the face with one." See: https://motherboard.vice.com/en_us/a...o-earths-orbit Using aerobraking is a rather touchy affair. It implies a high thrust impulse on the asteroid to begin the transfer orbit. A small impulse to use gravitational capture allows the use of an emergency escape engine to eject a failed capture. Except the rationale for using aerobraking is that you cannot paste a big enough engine on a target asteroid to stick it in orbit without using something like aerobraking to slow it down. Small vectoring to one of the L orbits and a mass limit rule would be an alternative. Again, how big an engine with how much fuel do you think you can lift up to an asteroid? Personally, I prefer 'lithobraking' by tossing them into a lunar crater and then sending a crew in to mine out the content by conventional means. Nobody gets hurt and it's easier than mining and smelting the things in deep space. -- "Insisting on perfect safety is for people who don't have the balls to live in the real world." -- Mary Shafer, NASA Dryden |
#5
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Scientists Map Out How to Nudge Small Asteroids into Earth?s Orbit
In article ,
ess says... On 4/09/2018 9:29 AM, wrote: "The notion of an asteroid headed for Earth is typically seen as a bad omen. On the flip side, some scientists and entrepreneurs increasingly see this scenario as a potential opportunity. Deliberately redirecting asteroids to our planet?s vicinity could enable us to study them up close, or even mine them. Given that these objects are packed with valuable resources, building a collection of them nearby could spark major advances in spaceflight, to say nothing of the scientific research that might result from easy access to these extraterrestrial bodies. A recent paper published in Acta Astronautica suggests that asteroids could be captured in Earth?s orbit with aerobraking, a maneuver that uses atmospheric drag to decelerate and position objects in stable trajectories around a planet. Aerobraking has helped place interplanetary spacecraft in orbit around Mars and Venus, and to slow down spacecraft returning to Earth. Led by Minghu Tan, a PhD student at the University of Glasgow, the paper immediately addresses the most obvious concern with this scenario: What if there?s some mistake in the redirect process and an asteroid accidentally impacts Earth? It?s bad enough that the dinosaurs were oblivious to their doomsday space rock, but it would be especially embarrassing if we humans smack ourselves in the face with one." See: https://motherboard.vice.com/en_us/a...o-earths-orbit After the aerobraking pass, you need to raise its perigee quite a lot, or it's just going to come back and burn up, either on the next pass, or some subsequent pass. The article doesn't say how the perigee would be raised. Unless they're planning on using a lunar flyby, I don't see how you can do this without a sufficiently large rocket engine. I'm not an expert in orbital mechanics but I do agree you have to somehow raise the perigee after the aerobraking pass(es) is(are) done. Giving that we're talking about a hugely massive object, this seems a big ask. Yep. I'd rather drop Kuiper belt objects on Mars myself. No danger to humans on earth. :-) Jeff -- All opinions posted by me on Usenet News are mine, and mine alone. These posts do not reflect the opinions of my family, friends, employer, or any organization that I am a member of. |
#6
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Scientists Map Out How to Nudge Small Asteroids into Earth?s Orbit
Maybe it would be safer to just grab the "mini moons" that Earth captures
periodically: "But new research has unearthed (...unmooned?) evidence that our planet occasionally captures “mini-moons” every once in a while. These tiny asteroids zoom around our planet as temporary natural satellites." See: https://bigthink.com/mike-colagrossi...ou-might-think |
#7
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Scientists Map Out How to Nudge Small Asteroids into Earth?sOrbit
Maybe it would be safer to just grab the "mini moons" that Earth
captures periodically: "But new research has unearthed (...unmooned?) evidence that our planet occasionally captures “mini-moons” every once in a while. These tiny asteroids zoom around our planet as temporary natural satellites." Wouldn't it be easier since it's already in Earth capture? See: https://bigthink.com/mike-colagrossi...ou-might-think |
#8
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Scientists Map Out How to Nudge Small Asteroids into Earth?s Orbit
William Elliot wrote on Tue, 4 Sep 2018 22:18:35
-0700: Maybe it would be safer to just grab the "mini moons" that Earth captures periodically: "But new research has unearthed (...unmooned?) evidence that our planet occasionally captures mini-moons every once in a while. These tiny asteroids zoom around our planet as temporary natural satellites." Wouldn't it be easier since it's already in Earth capture? Easier, no doubt, but you'd kind of like to pick something worth mining and relying on random chance is unlikely to deliver that very often. -- "The reasonable man adapts himself to the world; the unreasonable man persists in trying to adapt the world to himself. Therefore, all progress depends on the unreasonable man." --George Bernard Shaw |
#9
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Scientists Map Out How to Nudge Small Asteroids into Earth?sOrbit
On Sept./4/2018 at 06:44, Jeff Findley wrote :
In article , ess says... On 4/09/2018 9:29 AM, wrote: "The notion of an asteroid headed for Earth is typically seen as a bad omen. On the flip side, some scientists and entrepreneurs increasingly see this scenario as a potential opportunity. Deliberately redirecting asteroids to our planet?s vicinity could enable us to study them up close, or even mine them. Given that these objects are packed with valuable resources, building a collection of them nearby could spark major advances in spaceflight, to say nothing of the scientific research that might result from easy access to these extraterrestrial bodies. A recent paper published in Acta Astronautica suggests that asteroids could be captured in Earth?s orbit with aerobraking, a maneuver that uses atmospheric drag to decelerate and position objects in stable trajectories around a planet. Aerobraking has helped place interplanetary spacecraft in orbit around Mars and Venus, and to slow down spacecraft returning to Earth. Led by Minghu Tan, a PhD student at the University of Glasgow, the paper immediately addresses the most obvious concern with this scenario: What if there?s some mistake in the redirect process and an asteroid accidentally impacts Earth? It?s bad enough that the dinosaurs were oblivious to their doomsday space rock, but it would be especially embarrassing if we humans smack ourselves in the face with one." See: https://motherboard.vice.com/en_us/a...o-earths-orbit After the aerobraking pass, you need to raise its perigee quite a lot, or it's just going to come back and burn up, either on the next pass, or some subsequent pass. The article doesn't say how the perigee would be raised. Unless they're planning on using a lunar flyby, I don't see how you can do this without a sufficiently large rocket engine. If you can nudge it enough to get it to do aero-braking, it shouldn't be a problem to raise the perigee. One can imagine an extreme case where the asteroid was going to pass 200 km above Earth's surface and you can just barely nudge a little lower for aero-braking and then aren't able to raise the perigee fast enough. But a big asteroid being on such a trajectory isn't very likely. And those deciding to capture it being smart enough to be able to nudge into the atmosphere, yet too stupid to notice the danger isn't likely either. (People too stupid to see the danger aren't hard to find, it's the combination with smart enough to be able to nudge it that isn't likely.) So I wouldn't be too scared about that. Another thing that could be a problem is that you could mess up the atmosphere if you do this with a big asteroid. Personally, I would prefer doing a capture by selenic gravity assist. I'm not an expert in orbital mechanics but I do agree you have to somehow raise the perigee after the aerobraking pass(es) is(are) done. I would expect that for a somewhat big asteroid, there would be several aero-braking passes and that you would do small tweaks to the orbit after each pass. Alain Fournier |
#10
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Scientists Map Out How to Nudge Small Asteroids into Earth?sOrbit
On 6/09/2018 6:18 AM, Alain Fournier wrote:
On Sept./4/2018 at 06:44, Jeff Findley wrote : In article , ess says... On 4/09/2018 9:29 AM, wrote: "The notion of an asteroid headed for Earth is typically seen as a bad omen. On the flip side, some scientists and entrepreneurs increasingly see this scenario as a potential opportunity. Deliberately redirecting asteroids to our planet?s vicinity could enable us to study them up close, or even mine them. Given that these objects are packed with valuable resources, building a collection of them nearby could spark major advances in spaceflight, to say nothing of the scientific research that might result from easy access to these extraterrestrial bodies. A recent paper published in Acta Astronautica suggests that asteroids could be captured in Earth?s orbit with aerobraking, a maneuver that uses atmospheric drag to decelerate and position objects in stable trajectories around a planet. Aerobraking has helped place interplanetary spacecraft in orbit around Mars and Venus, and to slow down spacecraft returning to Earth. Led by Minghu Tan, a PhD student at the University of Glasgow, the paper immediately addresses the most obvious concern with this scenario: What if there?s some mistake in the redirect process and an asteroid accidentally impacts Earth? It?s bad enough that the dinosaurs were oblivious to their doomsday space rock, but it would be especially embarrassing if we humans smack ourselves in the face with one." See: https://motherboard.vice.com/en_us/a...o-earths-orbit After the aerobraking pass, you need to raise its perigee quite a lot, or it's just going to come back and burn up, either on the next pass, or some subsequent pass. The article doesn't say how the perigee would be raised. Unless they're planning on using a lunar flyby, I don't see how you can do this without a sufficiently large rocket engine. If you can nudge it enough to get it to do aero-braking, it shouldn't be a problem to raise the perigee. One can imagine an extreme case where the asteroid was going to pass 200 km above Earth's surface and you can just barely nudge a little lower for aero-braking and then aren't able to raise the perigee fast enough. But a big asteroid being on such a trajectory isn't very likely. And those deciding to capture it being smart enough to be able to nudge into the atmosphere, yet too stupid to notice the danger isn't likely either. (People too stupid to see the danger aren't hard to find, it's the combination with smart enough to be able to nudge it that isn't likely.) A small nudge a long way out can be enough to direct it towards the Earth. But after the aerobraking, you don't have that option. You need to raise its perigee quite a lot. So I wouldn't be too scared about that. Another thing that could be a problem is that you could mess up the atmosphere if you do this with a big asteroid. Personally, I would prefer doing a capture by selenic gravity assist. I'm not an expert in orbital mechanics but I do agree you have to somehow raise the perigee after the aerobraking pass(es) is(are) done. I would expect that for a somewhat big asteroid, there would be several aero-braking passes and that you would do small tweaks to the orbit after each pass. Alain Fournier |
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